crawlSpider 似乎不遵守规则 [英] crawlSpider seems not to follow rule

问题描述

这是我的代码.实际上我按照使用 Scrapy 递归抓取网页"，看来我在某处包含了一个错误.

here's my code. Actually I followed the example in "Recursively Scraping Web Pages With Scrapy" and it seems I have included a mistake somewhere.

有人可以帮我找到吗?这让我发疯了，我只想要所有结果页面的所有结果.相反，它给了我第 1 页的结果.

Can someone help me find it, please? It's driving me crazy, I only want all the results from all the result pages. Instead it gives me the results from page 1.

这是我的代码:

import scrapy

from scrapy.selector import Selector
from scrapy.spiders import CrawlSpider, Rule
from scrapy.http.request import Request
from scrapy.contrib.linkextractors.sgml import SgmlLinkExtractor

from githubScrape.items import GithubscrapeItem


class GithubSpider(CrawlSpider):
    name = "github2"
    allowed_domains = ["github.com"]

    rules = (
        Rule(SgmlLinkExtractor(allow=(), restrict_xpaths=('//*[contains(@class, "next_page")]')), callback='parse_items', follow=True),
    )

    def start_requests(self):

        baseURL = 'https://github.com/search?utf8=%E2%9C%93&q=eagle+SYSTEM+extension%3Asch+size%3A'
        for i in range(10000, 20000, +5000):
            url = baseURL+str(i+1)+".."+str(i+5000)+'&type=Code&ref=searchresults'
            print "URL:",url
            yield Request(url, callback=self.parse_items)


    def parse_items(self, response):

        hxs = Selector(response)
        resultParagraphs = hxs.xpath('//div[contains(@id,"code_search_results")]//p[contains(@class, "title")]')

        items = []
        for p in resultParagraphs:
            hrefs = p.xpath('a/@href').extract()
            projectURL = hrefs[0]
            schemeURL = hrefs[1]
            lastIndexedOn = p.xpath('.//span/time/@datetime').extract()

            i = GithubscrapeItem()
            i['counter'] = self.count
            i['projectURL'] = projectURL
            i['schemeURL'] = schemeURL
            i['lastIndexedOn'] = lastIndexedOn
            items.append(i)
        return(items)

推荐答案

我在您传递的链接上没有找到您的代码，但我认为问题在于您从不使用规则.

I didn't find your code on the link you passed, but I think the problem is that you are never using the rules.

Scrapy 通过调用 start_requests 方法开始爬行，但规则被编译并在 parse 方法上使用，您没有使用该方法，因为您的请求直接来自 start_requests 到 parse_items.

Scrapy starts crawling by calling the start_requests method, but the rules are compiled and used on the parse method, which you are not using because your requests go directly from start_requests to parse_items.

如果您希望在该级别应用规则，您可以删除 start_requests 方法上的 callback.

You could remove the callback on the start_requests method if you want the rules to be applied on that level.

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